Stem Cell Marker Controls Pair of Key Cancer Pathways

MONDAY, April 14 -- New findings by researchers suggest breast cancer may arise from stem cells and that targeting a certain gene linked to these cells may be a key to treatment.

Researchers from Georgetown University Medical Center report that the Musashi1 (Msi1) gene can flip open two known cancer pathways in mammary cells. The gene had been shown in previous studies to be a stem cell marker in several parts of the body.

The findings were expected to be presented April 14 at the annual meeting of the American Association for Cancer Research (AACR) in San Diego.

"This is the first time any role has been attributed to this gene, and it turns out to be one that is surprisingly powerful," study lead author, Xiaoyang Wang, a postdoctoral fellow at Georgetown's Lombardi Comprehensive Cancer Center, said in a prepared statement.

The study, done in a laboratory setting, shows the Msi1 gene regulates cell signaling in two mammary cells pathways -- Wnt and Notch. Both pathways help regulate stem cell growth, and past studies have tabbed them as critical players in the development of many cancers.

The researchers work also uncovered that Msi1 is expressed in particularly aggressive tumors. This finding fuels a debate among cancer researchers following recent studies indicating stem cells may be the root cause of some cancers.

"It is really critical to understand if stem cells are involved in cancer development, because a lot of therapies used to treat cancer don't target stem cells," study senior author Robert Glazer, a Georgetown professor of oncology and pharmacology, said in a prepared statement. "That may explain why tumors come back."

Wang concluded: "This work suggests, but does not prove, that stem cells drive breast cancer formation. Msi1 might make a good therapeutic target, and we are currently testing ways to interfere with its function in cells to see if it disrupts cancer cell proliferation."